5.4-stable review patch. If anyone has any objections, please let me know.
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From: Mengbiao Xiong xisme1998@gmail.com
[ Upstream commit 181698af38d3f93381229ad89c09b5bd0496661a ]
When CONFIG_CRYPTO_DEV_CCP_DEBUGFS is enabled, rebinding the ccp device causes the following crash:
$ echo '0000:0a:00.2' > /sys/bus/pci/drivers/ccp/unbind $ echo '0000:0a:00.2' > /sys/bus/pci/drivers/ccp/bind
[ 204.976930] BUG: kernel NULL pointer dereference, address: 0000000000000098 [ 204.978026] #PF: supervisor write access in kernel mode [ 204.979126] #PF: error_code(0x0002) - not-present page [ 204.980226] PGD 0 P4D 0 [ 204.981317] Oops: Oops: 0002 [#1] SMP NOPTI ... [ 204.997852] Call Trace: [ 204.999074] <TASK> [ 205.000297] start_creating+0x9f/0x1c0 [ 205.001533] debugfs_create_dir+0x1f/0x170 [ 205.002769] ? srso_return_thunk+0x5/0x5f [ 205.004000] ccp5_debugfs_setup+0x87/0x170 [ccp] [ 205.005241] ccp5_init+0x8b2/0x960 [ccp] [ 205.006469] ccp_dev_init+0xd4/0x150 [ccp] [ 205.007709] sp_init+0x5f/0x80 [ccp] [ 205.008942] sp_pci_probe+0x283/0x2e0 [ccp] [ 205.010165] ? srso_return_thunk+0x5/0x5f [ 205.011376] local_pci_probe+0x4f/0xb0 [ 205.012584] pci_device_probe+0xdb/0x230 [ 205.013810] really_probe+0xed/0x380 [ 205.015024] __driver_probe_device+0x7e/0x160 [ 205.016240] device_driver_attach+0x2f/0x60 [ 205.017457] bind_store+0x7c/0xb0 [ 205.018663] drv_attr_store+0x28/0x40 [ 205.019868] sysfs_kf_write+0x5f/0x70 [ 205.021065] kernfs_fop_write_iter+0x145/0x1d0 [ 205.022267] vfs_write+0x308/0x440 [ 205.023453] ksys_write+0x6d/0xe0 [ 205.024616] __x64_sys_write+0x1e/0x30 [ 205.025778] x64_sys_call+0x16ba/0x2150 [ 205.026942] do_syscall_64+0x56/0x1e0 [ 205.028108] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 205.029276] RIP: 0033:0x7fbc36f10104 [ 205.030420] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 e1 08 2e 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5
This patch sets ccp_debugfs_dir to NULL after destroying it in ccp5_debugfs_destroy, allowing the directory dentry to be recreated when rebinding the ccp device.
Tested on AMD Ryzen 7 1700X.
Fixes: 3cdbe346ed3f ("crypto: ccp - Add debugfs entries for CCP information") Signed-off-by: Mengbiao Xiong xisme1998@gmail.com Reviewed-by: Tom Lendacky thomas.lendacky@amd.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/crypto/ccp/ccp-debugfs.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/crypto/ccp/ccp-debugfs.c b/drivers/crypto/ccp/ccp-debugfs.c index a1055554b47a..dc26bc22c91d 100644 --- a/drivers/crypto/ccp/ccp-debugfs.c +++ b/drivers/crypto/ccp/ccp-debugfs.c @@ -319,5 +319,8 @@ void ccp5_debugfs_setup(struct ccp_device *ccp)
void ccp5_debugfs_destroy(void) { + mutex_lock(&ccp_debugfs_lock); debugfs_remove_recursive(ccp_debugfs_dir); + ccp_debugfs_dir = NULL; + mutex_unlock(&ccp_debugfs_lock); }